Line Issues After Regrade

I just recently (couple days back) finally switched ISP and regraded from a fixed 2mbit Product (via Pipex) to ADSLMax with Fast.co.uk.

At first I was rather surprised to see it only sync at 6624, given that my Line Attenuation / SNR previously was around 27dB (Att) and 24dB (SnR).

After some testing / rerouting of wiring etc.. I was getting 7616 sync speed and 8-10dB SnR via the test socket, but only 6624 sync and 6dB SnR with extention plugged in. Found some pretty shoddy wiring job done by the previous BT engineer and after putting that right, I now see 7616 sync and 8-10dB SnR, both from the test socket and the faceplate, with phones all plugged in etc..

However, I have also noticed that for no aparent reason, sometimes when the line syncs, I get huge numbers of FEC errors on the Upstream, right from the start (Increasing at a rate of over 100 per second). However if i drop the line and resync, sometimes itll do it again, while another time, it will be perfect, no errors at all...

Whats concerning me is that these errors seem to acumulate to a point where the line drops anyway, which is messin around with my IP profile etc..

Im gettin perfectly good throughput on upload and the line stats are still perfect on the upload side, so not really sure whats causing this, but its a concern, as its causing interleaving to be on the line, adding a nice chunk to my ping and dropping the sync speed (If I remember rightly, an interleaved line will only sync up to a max of 7616 due to overheads?)


My Current line stats (with a good sync, no FEC errors from the start this time).

Modem State : SHOWTIME_L0
Remote Report : Showtime
Last Failure :
Time Connected : 01:05:11
Modulation : ANSI
Rate Us/Ds (Kbps) : 448 7616
Cap. Occupation Us/Ds (%) : 58 96
Noise Margin Us/Ds (dB) : 24 8
Attenuation Us/Ds (dB) : 13 26
Output Power Us/Ds (dBm) : 12 19
FEC Errors Us/Ds : 0 0
CRC Errors Us/Ds : 0 0
HEC Errors Us/Ds : 0 0
Driver Version : 0.0.0
Firmware Version : PCI-AML-1-0.4-0.1.0.10


So can anyone help shine a light on what could be causing these issues? Id really like to get it sorted so that (hopefully) I wont need to have interleaving on the line and can get the full 8128 sync speed that is expected on my line (both via BT checker and various other types of "calcs" that use line attenuation etc.. to give an estimate) and more importantly, get rid of interleaving so that my ping drops back to where it used to be on my fixed 2Mbit product.

Hmm, something seems to be wrong now,

Time Connected : 10:50:34
Modulation : ANSI
Rate Us/Ds (Kbps) : 448 7616
Cap. Occupation Us/Ds (%) : 58 96
Noise Margin Us/Ds (dB) : 24 8
Attenuation Us/Ds (dB) : 13 26
Output Power Us/Ds (dBm) : 12 19
FEC Errors Us/Ds : 18086 1
CRC Errors Us/Ds : 17578 3
HEC Errors Us/Ds : 14739 3


FEC errors are going up at a rate of about 100 per sec, (getting to around 65k then loopin back to 0)
CRC errors are goin up too at around 10 a sec, with HEC doing roughly the same.. Suddenly started happening around 11:30pm or so, my downstream throughput is now down at like 2.5meg acordin to speedtesters, even tho upload is still going at 386kbit without a problem.

Not really sure whats goin on tbh, my Attenuation is still good (and hasnt changed since daytime), as is my SnR. 1 Thing I have possibly just thought of is that around 11:30pm Im pretty sure it was raining quite hard, tho i have never before noticed any connection problems or disconnects during bad weather, Is it possible water is getting in somewhere? What effect would you likely see if there was water ingress into a line or similar?

1 Reason that I ask is that while I was in the loftspace fixing the phone extention into another room, I decided to to tack up (using cable clips) the phone line to one of the trusses to move it away from some electrical cables that were running along the rafters. While doing this I noticed a small ammount of water at the end of the black "hardline" into the house, where it went into a white plastic box (Im asuming a coupler) and came out as white internal wiring. I wiped my hand up the line tho it was all dry on the outside, and there was no evidence of water ingress into the loftspace or on the walkboards.

Is it possible there is a "chink" in the outer sheath of the hardline between my property and the pole and water inside the line is causing these errors?

Thanks

Have you disconnected all the ring wires ?

All those errors are upstream. Upstream uses frequencies closer to voice so it seems something is screwing up those low end frequencies and the most likely culprit imo is either a duff filter or something unfiltered. Another possibility given your recent DIY is that you've nailed through the cable so check that carefully too.

It could also be something wrong with your port at the exchange I suppose but you need to eliminate the far more likely error at your end - take off the faceplate and run a while using the inner test socket to see how that goes.

The other possibility is that your router is telling you porkies. With that level of errors even if they are upstream only your connection must be struggling.

Edited by kwikbreaks (Wed 25-Mar-09 08:18:30)

If the router is syncing at 7616 all the time this will not mess up the IP Profile, i.e. this only drops in response to the modem syncing at a lower speed.

In reply to a post by kwikbreaks:

All those errors are upstream. Upstream uses frequencies closer to voice so it seems something is screwing up those low end frequencies and the most likely culprit imo is either a duff filter or something unfiltered. Another possibility given your recent DIY is that you've nailed through the cable so check that carefully too.

It could also be something wrong with your port at the exchange I suppose but you need to eliminate the far more likely error at your end - take off the faceplate and run a while using the inner test socket to see how that goes.

The other possibility is that your router is telling you porkies. With that level of errors even if they are upstream only your connection must be struggling.

LOL its most certainly not a nail through a wire, I said i clipped the wire up, not that Im inept at DIY and shoved a nail through a wire And to the last point, yes, my connection most certainly is struggling. It was especially noticeable that the errorcount only started to go crazy around the time it was hammering down with rain. Is it possible that water in the circuit / line somewhere could be causing interfearance between the voice and ADSL frequencies?

It was most noticeable that about an hour after the rain stopped and for the next couple hours, the errorcounts began to slow again, until around 3hrs after they were going crazy, they had slowed again to a point where I was no longer getting CRC and HEC errors (or at most, a couple a minute), but still quite a number of FEC errors, which seems to reflect the symptoms of something getting water in it, then slowing drying out after the rain, would you agree?

Also, is it adviseable to go to a neighbours / friends house elsewhere and attempt a "Quiet line test" first to try and get a benchmark for what to listen to? I currently have a cordless phone and while I cant really notice any popping etc.. there is a quiet sorta buzz / hiss, but Unsure as to whether this is on the line, or just the phone etc.. And Im guessing since my line really seemed to go crazy durin the rain, it would again make more sense to test my line during the rain.

In reply to a post by MrSaffron:

If the router is syncing at 7616 all the time this will not mess up the IP Profile, i.e. this only drops in response to the modem syncing at a lower speed.

Well, today after gettin up it seems the errors got the better of the system as its now resynced at 6880 and with 9dB+ on downstream SnR, so it appears its not only causing my target SnR to go up, but the sync speed to be dropped also...

Id really like some help with possibly symptoms of water ingress etc.. as the longer this goes unfixed, the more errors will build up and the higher my target SnR will keep going (aswell as the lower my sync speed will keep dropping).

Given my distance to exchange (as the crow flies) is around 1.2kms and my line attenuation etc.. is good, I see no reason why I shouldnt be hitting 8128 with fastpath (not interleave) unless there is clearly an error on the line somewhere.

Edited by DeviIman (Wed 25-Mar-09 15:19:20)

Sorry to cast aspersions but the most recent known change with your line apart from the sudden increase in errors appears to be your DIY so that is certainly suspect imo. Simply clouting the wire could have crushed off the insulation inside and left a partial short.

I doubt that the problem is water ingress into a cable run but there are some BT bods visit this board so maybe they'll comment on that with more knowledge and experiarence than me. The usual problem reported to do with water is when joints have been laying in it and have eventually corroded. Water does have an adverse effect on TV coax if it gets in.

Hehe, thats fair enough, was only jokin around anyway But in all seriousness, the errors were showing up before doing the cable job, I did that in an attempt to get the line away from several electical cables in the loftspace just incase that was possibly causing any issue...

While I agree that water inside the outer black "sheath" may not cause too much of an issue, it does raise other questions which is that if water is in the line, what else is it in? Has it run back along the line and into the junctionbox type thing on the post? Given the way the errors behaved during / after the rain late last night, I am finding it quite likely it could be water.

Unfortunatly having not done the "quiet line test" before its always hard to say exactly how quiet it should be, or whether what I am hearing is just hum from the phone itself (and since the errors were most prevelant during the rain, It seems much more likely to hear something untoward on the voice part of the circuit).


Also having been checking things again, I find that while there is a very slight "drip loop" on the cable from the pole to the "anchor point" on the building, from there, down to the hole in the wall into the loftspace, is just a straight downward drop and there is no kind of caulking in the hole either, can see daylight through it. However as previously mentioned, when I did feel a bit of water at the end of the black "hardline" where it went into its coupler (to switch to white internal wiring), there was no sign this water had come down the outside of the cable, as it was dry right back to the wall, aswell as no sign of water coming through the hole or anywhere else for that matter.

1 Minor cause for concern is that I have found an abraison mark on the hardline around 8-10 inches from the anchorpoint which seems quite deep, You cannot exactly see the conductors inside, however it does appear as tho you can see a "change in appearance" of the cable in the abraison, of around 1mm - 1.5mm wide, which I guess could possibly be one of the conductors (or possible reinforcing cables) starting to wear? (I think if I remember rightly the hardline has a few heavier red cables inside it to support the weight of the cable?)

Well as the errors were present before the DIY that can now be discounted.

To rule out a duff or missing filter you need to connect the the test socket behind the faceplate on the master (you'll either need to use a spare filter or an adaptor to plug the router in there). If you still see the errors accumulating connected up like that then I reckon you need to call the ISP and report it as a fault.

All that water normally does inside cables is oxidise the copper which is obvious - it's black. Once the outside is blacked up it doesn't usually go deeper and cause a break. It could still be water screwing you up though.

The fact that the errors all seem to be upstream indicates an unusual problem imo.

In reply to a post by kwikbreaks:

Well as the errors were present before the DIY that can now be discounted.

To rule out a duff or missing filter you need to connect the the test socket behind the faceplate on the master (you'll either need to use a spare filter or an adaptor to plug the router in there). If you still see the errors accumulating connected up like that then I reckon you need to call the ISP and report it as a fault.

All that water normally does inside cables is oxidise the copper which is obvious - it's black. Once the outside is blacked up it doesn't usually go deeper and cause a break. It could still be water screwing you up though.

The fact that the errors all seem to be upstream indicates an unusual problem imo.

Yeh I noticed right away (as commented on in the first post) that sometimes when it synced, I would see tons of FEC errors right from the start, while another time it would show no errors at all.

I too found it strange that the errors were all occuring on Upstream rather than Downstream. It is of course now, a bright sunny day and thus far I have no errors showing up on the line stats at all, coupled with the fact they started going crazy last night shortly after it started raining, and then slowly got better a couple hours after it stopped raining is, at least for me, really starting to point towards water somewhere.

Unfortunatly what I really need now is another rainy day so that I can conduct some test-socket checks and quiet-line checks to see if the problem is indeed related to rainwater, but as luck would have it, its a bright sunny day outside and coincidentally, I have no errors showing in router stats on Upstream or Downstream.